High voltage sources are used in a variety of applications including X-ray tubes, electron microscopes and particle accelerators. One of the most common methods of high voltage generation is the Full-Wave Cockcroft-Walton voltage multiplier (FWCW), where each stage consists of three capacitors and four diodes. The aim of this work is to introduce a circuit design that provides a high voltage...
Relativistic, high intensity and small emittance electron bunches are the basis of linear collider and FEL projects. With this talk, our interest focused on wakefields generated by using dielectric based structures. We consider Dielectric Disk Accelerating (DDA) and other dielectric structure designs. The electrical properties of low loss ceramic, fused silica and diamond like materials will...
Plasma beam dumps use the large decelerating wakefields sustained by plasmas to achieve compact deceleration of spent beams. Besides the higher efficacy to absorb beam energy, plasma beam dumps are also safer if compared to conventional beam dumps. This is due to the lower production of radioactivation hazards in the low-density plasma medium. In this work, existing analytical models to...
Utilizing photonic nanostructures and ultra-short laser pulses, dielectric laser acceleration (DLA) provides a scheme for high gradient particle accelerators. In the past, this concept was limited by insufficient beam transport through longer structures and the inability to stage multiple structures without particle loss. The concept of alternating phase focusing (APF) provides a way to...
A goal of ESCULAP [1,2] experiment is the external injection of photo-injector electrons bunch with consequent LWFA acceleration in the moderate density plasma cell.
In our configuration small fraction of LASERIX laser is send to the photocathode, and the rest is delivered to the plasma cell for the wake excitation.
Stability of the laser beam, its shape, “flatness”, duration, intensity...
In accelerator physics, high energy THz radiation can be used for different purposes e.g. diagnostic, magnetic lenses, acceleration etc. For this purpose, it is needed a reliable source of high energy THz pulse. Between these sources, Optical Rectification by organic crystals has the highest optical conversion efficiency.
We are going to present new broadband measurements, from ultraviolet...
Laser Plasma Accelerators (LWFAs) operating in the linear and quasi-linear regime require the driving laser pulse to be guided over the length of the accelerator stage. Multi-GeV plasma stages, for example, require the driving pulse to be guided over 100s of millimetres of plasma of density $n_\mathrm{e}(0) \approx 10^{17}~\mathrm{cm}^{−3}$. These challenging parameters can be met by...
In this work, I will theoretically show how the phase modulation of the infrared pump pulse, used to generate the terahertz radiation via the Optical Rectification Process (OR) in the regime of weak-pump signal, affects the amplitude and the phase of the resulting THz field. I will also discuss the effects of THz generation under strong-pump signal. This theory can be used in many practical...
It is shown that external magnetic fields at tens of tesla can provide additional control of electron injection in laser wakefield acceleration (LWFA). In the first case, we consider ionization injection assisted by a transverse magnetic field. Both the electron trapping condition and the wakefield structure are changed significantly by the magnetic field such that injection occurs over a...
The strong focusing down of intense laser pulses in air leads to the production of plasma-accelerated low-energy electrons. These particles are emitted almost isotropically and travel with an intense photon emission, which – when impacting matter – stimulate cathodo- and luminescence. This contemporaneous luminescence emission provoked by both electrons and photon has recently been referred to...
A highly efficient compact wakefield accelerator is being developed at Argonne National Laboratory for a future multiuser x-ray free electron laser facility [1]. A cylindrical metallic structure with a 2 mm internal diameter and fine corrugations on the wall is used to cause a Čerenkov radiation by a “drive” bunch at ~ 180 GHz in the fundamental mode and to obtain accelerating gradients on the...
Multi-pulse laser wakefield acceleration (MP-LWFA) is a promising scheme for increasing the repetition rate of LWFAs to to the kHz range [1-2] In this approach the laser wakefield is driven by a train of laser pulses spaced by the plasma wavelength such that the wakefields driven by each pulse interfere coherently.
A major consideration for MP-LWFA and related schemes is the decay time of...
Laser-driven plasma wakefield acceleration (LWFA) provides an innovative and compact alternative to conventional RF accelerators. The electron beam can be injected to a plasma accelerator using different techniques. The advantage of external injection from an RF accelerator is given by the possibility to inject fully characterized bunches with a well-controlled beam quality. In addition, the...
Many experiments have been conducted in recent years in which electron bunches have been accelerated during the interaction of ultra-short and ultra-intense laser pulses with thin solid targets. Several causes can be taken into consideration which contribute to the determination of the measured bunch length at the exit of the targets. These include the velocity distribution of the electrons...
The prime challenge of laser-plasma based accelerators at the moment is to optimise the particle beams to obtain a steady mono-energetic and collimated bunch of energetic particles with the maximum possible efficiency. The present work is dedicated to optimising the laser and plasma parameters, and examining the ion acceleration processes that are present due to the laser plasma interactions....
The interaction of high-power, high-contrast laser pulses with nanostructured targets has largely been explored as a possible way to increase energy absorption and aim to more efficient proton acceleration. In these studies, the costs of target manufacturing and handling are a key factor to establish the soundness of each approach, and while advance of laser technologies now allow preserving...
Laser-driven ion acceleration is an attractive way to realize compact and affordable ion sources for many exciting applications including cancer therapy. Many of these applications require high energy ion beams with narrow
energy spread as well as high flux. When a near critical (or rather overdense) target is irradiated by a laser pulse, ions are compressed to form a density spike, which in...
Beam-driven plasma wakefield accelerators (PWFAs) allow for high gradient acceleration of electron beams and hence are promising candidates for compact and cost-efficient drivers of applications demanding high brightness beams. One of the main challenges in these accelerators is to control beam-plasma instabilities with rapid growth rates which are induced by the strong transverse components...
A typical laser-plasma accelerator (LPA) is driven by single, relativistic laser pulse from terawatt or petawatt-class lasers. Recently, there have been simulation studies on the use of two synchronized ultrashort relativistic co-propagating two-color laser pulses (CTLP) for LPA research. Here, we present experimental results from the first LPA driven by CTLP where we observed a significant...
The report is devoted to the latest experimental results on the laser-driven acceleration of electrons obtained at the laser-plasma setup PEARL (IAP RAS, Russia). The main goal of the experimental campaign was to demonstrate in the laboratory an unmatched LPA regime, leading to higher acceleration gradients. Electrons with energies exceeding GeV were demonstrated for ~ 10 J, 50 fs laser pulses...
Particle acceleration beyond the few-MeV level currently requires large infrastructures, due to the low frequencies (a few GHz) and relatively low field amplitudes (a few tens of MV/m in the meter-long structures) used in conventional accelerating structures. One of the scheme currently investigated to reduce the footprint of particle accelerators by several orders of magnitude is to use...
The production of high-quality electron bunches in LWFA relies on the possibilities of both injecting ultra-low emittance bunches in the plasma wave and preserving their quality during the acceleration. Among the recently proposed ultra-low emittance LWFA schemes, the Resonant Multi-Pulse Ionization injection (ReMPI) [1] is flexible and relies on commercially available laser technology. In...
Dielectric laser acceleration is a versatile scheme to accelerate and control electrons with femtosecond laser pulses in nanophotonic structures. We show recent results of the generation of a train of electron pulses with individual pulse durations as short as 270 +/- 80 attoseconds. We achieve these attosecond micro-bunch trains based on two subsequent dielectric laser interaction regions...
To realise a 10 GeV laser plasma accelerator stage, high-intensity pulses must be guided through low-density ($\sim 1 \times 10^{17} \rm{cm^{-3}}$) plasma over distances of order 100s of millimeters.
We recently presented simulations which showed that plasma channels with these parameters could be generated by the hydrodynamic expansion of optical-field-ionised plasma columns formed with an...
Fine time-resolved analysis of matter - i.e. spectroscopy and photon scattering - in the linear response regime requires fs-scale pulsed, high repetition rate, fully coherent X-ray sources. A seeded FEL driven by a Linac based on Super Conducting cavities, generating $10^{8}$-$10^{10}$ coherent photons at 2-5 keV with 0.2-1 MHz of repetition rate, can address this need. Three different seeding...
In the context of plasma wakefield acceleration beam driven, we design and numerically test an ideal working point that exploits the resonant behavior of a train of driving bunches with ramped charge in order to accelerate a trailing bunch to high energy. The working point consists in a train of four bunches generated by an RF X-band photo-injector with the energy of 1.2 GeV. The bunch current...
Plasma wakefield accelerators can provide gigavolt-per-centimetre energy gain, offering a promising path towards compact electron sources. They rely on the generation of plasma waves driven by either a high-current charged particle beam (PWFA) or an intense laser pulse (LWFA).
PWFAs offer particularly attractive regimes of injecting and accelerating a new high-quality electron beam, but...
High-gradient high-frequency accelerating structures are in strong demand for the next generation of compact light sources. Accelerating structures operating in Ka-Band are foreseen to achieve gradients around 150 MV/m. Among possible applications of a Ka-Band accelerating structure we refer to the beam phase-space manipulation for the Compact Light XLS project as well and medical and...
The MariX project (Multi-disciplinary Advanced Infra-structure for Research with X-rays) is a free electron laser (FEL) light source proposed by the INFN-Milan. It will produce highly coherent X-rays, in the range 0.2-8 keV, with ultra-short pulses (10-50 fs) and a repetition rate up to 1MHz. At the same time, MariX will host a compact monochromatic X-ray source, called BriXS, by using an...
The FEL beam conditioning has been proposed 30 years ago as a method to mitigate an excessive electron beam emittance, which at that time was considered the principal limiting factors for the SASE FEL development at short wavelengths. In essence, the beam conditioning implies artificially inducing at the undulator entrance a correlation in the electrons’ energies and intra-undulator betatron...
Applications such as colliders and plasma wake field acceleration require high gradient quadrupoles, in the range of 400-500 T/m and with a bore of few millimeters in diameter.
The design of a tunable high gradient permanent magnet quadrupole, based on the QUAPEVA design developed for the SOLEIL synchrotron, is presented. The quadrupole has a fixed part made of a Halbach quadrupole surrounded...
The advent of laser wakefield acceleration of electrons to GeV energies and charges up to nanocoulombs offer a unique tool to generate high intensity bremsstrahlung with characteristics similar to conventional accelerators, but in a more compact setup. Future facilities like the ELI pillars will use laser-generated bremsstrahlung at high repetition rates to study nuclear physics phenomena....
The MariX FEL is a compact GeV-class X-ray source exploiting a two-pass 2-way acceleration in a Super-Conducting linac operated in continuous wave mode. A key component of this peculiar machine layout is the Arc Compressor (AC), a 300 m long beamline consisting of 14 "Double Bend Achromat" cells and a bidirectional quadrupole focusing channel, which allows the beam to be u-turned while it is...
Beam-driven plasma wakefield accelerators allow for the generation and subsequent acceleration of electron beams inside the plasma
with substantially lower emittance than the driving electron beam, eventually providing technology for final-focus brightness converters for versatile applications. Among a variety of internal injection techniques, density downramp injection has the potential to...
Free Electron Lasers (FEL) are commonly regarded as the potential key application
of laser wakefield accelerators (LWFA), but up to now the relatively high energy spread has prohibited FEL lasing. In order to overcome this limitation, modified undulator schemes, so-called transverse gradient undulators (TGUs), were proposed and a first superconducting TGU was built at Karlsruhe Institute of...
The field of plasma acceleration has undergone rapid advancement in recent years, with significant progress being made towards the production of stable high quality electron beams. With this progression comes new avenues of research into potential applications, facilitating the need for precise understanding and control of the femtosecond-micrometer scale interaction process. Experimental...
External injection is a promising method to achieve high accelerating gradients and to control the beam properties. The energy gain of an electron via the wakefield is proportional to the product of the accelerating field multiplied by the effective propagation distance of the laser. Therefore, in order to bring the electron energy to the order of the $GeV$, a longer propagation length is...
The acceleration of electrons with ultra-short, high-intensity laser pulses has a successful method. Although, the maximum accelerated electron energy is limited mostly due to de-phasing of the electrons with the driving laser pulse and the depletion of the laser pulse. Staging two laser wakefield accelerators with two laser beams can overcome these limitations. Using the first plasma cell for...
In the poster we will describe the most recent experimental results obtained at the Laser Light Ion beam-Line using both flat and nanostructured thin foil targets, where accelerated ions were characterized using a wide range of detection techniques, optimized for the severe conditions typical of a laser-plasma acceleration environment.
Advanced targets are also being explored to enhance...
Terahertz-driven electron beam manipulation promises femtosecond control of bunches with femtosecond timing jitter. A compact, terahertz-driven velocity bunched electron beam demonstration is under development at the Cockcroft Institute. A lithium niobate terahertz radiation source using the tilted pulse front scheme has been established experimentally and its interaction with a 100 keV...
Few-cycle shadowgraphy is a common tool to qualitatively investigate the longitudinal and transverse structure of laser generated wakefields. However the measured intensity distribution provides hardly any information about the wake amplitude since the wakefield itself is a pure phase object and the measured intensity distribution is a function of the imaging plane. Commonly this plane is not...
The recent activities of the SPARC_LAB test-facility (LNF-INFN) are focused on the study of the interaction of high-brightness electron beams with plasmas and on tests on new advanced diagnostics. Here we report the latest results, showing the progress toward plasma acceleration and demonstrating the use of plasmas to shape the beam longitudinal and transverse profiles.
We theorerically demonstrate a possibility to resonantly accelerate electrons by a moderately relativistic laser pulse (from $\sim 10^{19}-10^{20}$ W/cm${}^2$) interacting with the surface of a microstructured target with periodic grooves. If the structure period is equal to the laser wavelength, a resonant acceleration may occur and electron bunches can be accelerated up to high energies by...
Seeding of the drive bunch self-modulation (SM) process is essential when using a long particle bunch (σz>>λpe) to drive wakefields in plasma. Seeding in principle leads to a SM phase reproducible from event-to-event, allowing for deterministic injection of an electron witness bunch to be accelerated.
Since external injection requires generation of an electron bunch in an RF-gun or LWFA, we...
Plasma based technology will allow an unprecedented reduction of the size of accelerating machine. Both fundamental research and applied science and technology will take profit of this feature.
The same compactness is required downstream the accelerator module, where the plasma-accelerated beams usually experience a large angular divergences growth after the acceleration. Here compact, strong...
X-ray absorption spectroscopy can provide a wealth of information about a sample, including a simultaneous measurement of the temperature and structure of both the electrons and ions, via techniques such as XANES (X-ray Absorption Near Edge Structure). If these measurements can be made using a single ultrashort probe pulse at multi-keV energies, they provide a powerful tool for investigating...
The plasma photocathode particle-driven Wakefield accelerator (TH-PWFA) is a promising path towards ultrahigh 5D-brightness and multi-GeV electron beams for application such as X-Ray free-electron laser (XFEL), inverse Compton scattering (ICS) and High Energy Physics (HEP). Recent experimental breakthroughs within the "E210: Trojan Horse PWFA" collaboration obtained at Stanford Linear...
In order to measure emittance in single shot, it is necessary to obtain information about beam spot, angular divergence and correlation term. The former and the second terms can be provided by a simultaneous measurement of beam size and Optical Transition Radiation (OTR) angular distribution. The latter is acquired by means of a microlens array, producing several contiguous replicas of OTR...
We report on the status of the dielectric laser acceleration (DLA) experiments at the SINBAD/ARES linac at DESY, Hamburg. The experiments are performed in the context of the Accelerator on a CHip International Program (ACHIP). At SINBAD, the main goal is to show net energy gain of externally injected relativistic electron bunches in the high-gradient fields of a laser-illuminated dielectric...
The development of compact accelerator machines is leading towards plasma-based devices able to produce high accelerating gradients in the GV/m scale but, at the same time, with the aim of preserving the electron beam quality. The latter topic, for plasma-based accelerators, is strictly related to the plasma properties as stability, uniformity and reproducibility, which in turn depend on the...
The nascent technology of terahertz (THz)-based electron acceleration holds great promise for development of compact relativistic electron sources with femtosecond bunch durations suitable for applications from ultrafast electron diffraction to injectors for THz-based accelerators and light sources. These so-called “THz guns” present unique capabilities, but also unique challenges associated...
The AWAKE Run 1 experiment finished successfully its proof-of-concept program in 2018 by demonstrating the seeded self-modulation of a long proton bunch in plasma and accelerating externally injected electrons to GeV energies in 10m plasma.
AWAKE is now preparing for Run 2 planned to start in 2021 with the aim to achieve high-charge bunches of electrons accelerated to high energy, about 10...
When long particle beams (compared to the plasma skin depth) propagate in plasma, they can be subject to two competing transverse instabilities: beam hosing and self-modulation. Hosing disrupts the beam and is considered a detrimental effect. Conversely, the self-modulation process can be seeded and exploited in plasma wakefield acceleration experiments to excite high-amplitude wakefields,...
We discuss the use of high power laser-generated THz waves for acceleration and electron beam phase space manipulation. These find application both as a compact alternative for radiofrequency-based accelerators as well for high frequency manipulation of electron beam longitudinal phase spaces and beam compression. We’ll present our different approaches to reach next goal in THz acceleration...
Full characterisation of ultra-intense laser pulses not only requires their separate characterisation in space and time, but also measurement of the entire spatio-temporal field distribution $E(x,y,t)$. While a variety of techniques has been developed for this purpose (e.g. STARFISH, TERMITES or INSIGHT), most of them rely on spatial or temporal scanning and thus require some thousand shots...
The efficiency of electron bunch acceleration by wakefield, excited in two-beam electron-positron dielectric resonator collider by train of electron bunches is determined by transformer ratio [1-14]. Two trains are considered. First is train of homogeneous bunches, current grows linearly along a train. Current of the second train grows linearly along each bunch and train. The length of...
Dielectric wakefield structures driven by relativistic beams have been employed to generate high-gradients for collinear acceleration schemes, as well as for applications in beam phase space manipulations. In simple cylindrical dielectric structures, the longitudinal wakefields are also accompanied by transverse fields. The growth of the transverse fields can severely limit the acceleration...
Laser-plasma accelerators generate ultrarelativistic electron beams over only a few centimeters, making them particularly interesting as drivers for compact next-generation light sources. In order to become applicable for these applications, control of electron beam properties, enhanced stability and reproducibility are crucial.
Here, we demonstrate dedicated tuning of electron beam parameters...
ALEGRO, the Advanced LinEar collider study GROup is an international study group promoting advanced and novel accelerators (ANAs) for high-energy physics applications. ALEGRO organizes one workshop each year as well as meetings at prominent ANAs conferences (EAAC, AAC, etc.). ALEGRO also submitted an input to the European Strategy for Particle Physics Update (ESPPU) process and was represented...
High power laser facilities currently under construction will open up new accelerator applications, which will encounter quantum processes. Experiments such as Compton backscatter sources will require a thorough experimental understanding of non-classical behaviour. Recently, experiments have started to measure these effects in isolation by studying radiation reaction, using the collision...
